Recently, a price reduction and a capacity increase of a recording medium such as a memory card in accordance with DCF (Design rule for Camera File system) standard cause a user to store large volumes of image data taken by a digital camera. However, in the DCF standard, a strict limitation is imposed on a character string which can be used for a directory name (a folder name) and a file name, so that the user cannot manage the image data under a directory name or a file name which is familiar to the user. Moreover, the directory name and the file name in the DCF standard are designated only by capital alphabetical characters and numeric characters, so that the user cannot visually recognize each directory name or file name easily. Thus, there is a suggestion of a means which enables the user to search and display the directory and the image data easily.
For example, there is a known electronic camera device which associates a user comment, a shooting condition, or the like of an image data with the image data and makes a recording medium store them, and then creates a management file which stores a directory name, which conforms to DCF standard, and a directory name, which does not conform to the DCF standard, in the recording medium so that the image data can be easily searched (refer to patent document 1, for example).
Moreover, there is a known viewer device which uses a hierarchical directory structure and a directory name which do not conform to DCF standard to enhance a visibility and can display image data included in a predetermined directory or image data included under the predetermined directory as a slide show (refer to patent document 2).
However, the technique described in the patent document 1 is to search a directory or an image data which conforms to the DCF standard, so that it cannot deal with a directory and an image data which does not conform to the DCF standard by reason of changing the directory name or the file name. Moreover, the technique described in the patent document 1 is to make a search for each directory or image data, so that when a plurality of image data are displayed as a slide show, for example, all of the image data in the directory need to be displayed. Thus, the slide show of each cluster desired by the user cannot be displayed, and moreover, an amount of time for displaying the slide show of each directory increases.
In the technique described in the patent document 2, the image data included in the directory structure which does not conform to the DCF standard can be displayed as the slide show, however, the image data cannot be displayed on other equipment such as a digital television, a digital camera, a mobile phone, a digital photo frame, or the like which conforms to the DCF standard.